1. Field of the Invention
The present invention relates, in general, to the reduction of NO.sub.x emissions, and in particular to, a new and useful method for reducing NO.sub.x utilizing a plasma generator and molecular nitrogen and hydrocarbon mixture.
2. Description of the Related Art
Nitrogen oxides (NO.sub.x), such as NO and NO.sub.2, are among the most regulated combustion-generated pollutants known. NO.sub.x is formed in several different manners. One manner is the direct oxidation of molecular nitrogen (N.sub.2) which forms NO and is commonly referred to as thermal NO.sub.x. Reactions of molecular nitrogen and hydrocarbon radicals produce amines and cyano compounds which if oxidized form the so-called prompt NO.sub.x. NO.sub.x is also formed from the combustion of nitrogen-bearing fuels such as coals or oils.
Because the production of NO.sub.x has become such a major environmental problem, fuel pyrolysis in an oxygen deficient region has been used in order to produce species that react with NO.sub.x in order to convert it to molecular nitrogen. This method has been applied to many types of fossil fuel burners in order to provide NO.sub.x emissions control.
Another method for reducing NO.sub.x is to utilize plasma jets of nitrogen. Laboratory researchers utilized nitrogen atoms to remove NO from simulated flue gas. In that study, pure molecular nitrogen (N.sub.2) was disassociated to monatomic nitrogen (N) by passing the N.sub.2 through a high temperature, aerodynamically spun plasma arc. The principle reaction is described as: EQU N+NO.fwdarw.N.sub.2 +O
At another laboratory, a plasma torch was developed which was able to breakdown methane molecules and seed a natural gas flame with carbon radicals. The presence of these radicals reduced the thermal NO.sub.x through enhanced flame luminosity and radiative heat loss.
Up till now, most of the other NO.sub.x reduction methods utilizing plasma generation have involved only nitrogen or natural gas as pointed out above. Presently, there is no known system or method for providing a higher formation of NO.sub.x reducing species through plasma generation.